Bluetooth port assignments

I have several questions regarding bluetooth port assignments and winXP. Is there any advantage or disadvantage to higher port numbers (10-15)? Is there any way to force specific bluetooth port assignments? I am uploading GPS information to a tablet computer running XP Tablet for a navigation program. When I add a bluetooth device (the GPS receiver), it always seems to push the port assignment up above 6. It would be very helpful for me to force a port assignment of 6 or less because I am using Franson GPS Gate as an interface to the nav program. Any help would be greatly appreciated.

TIA